Method of and apparatus for manufacturing articles



Jan. 19, 1937. w. B. BOHANNON 2,063,367

METHOD OF AND APPARATUS FOR MANUFACTURING ARTICLES 2 Sheets-Sheet 1 Filed April 5, 1954 INVENTOR ZRA! MAI- M ATTORNEY Jan. 19, 1937. -w. B. BOHANNON 2,068,367

METHOD OF AND APPARATUS FOR MANUFACTURING ARTICLES Filed April.5, 1934 2 Sheets-Sheet 2 FIG. 4.

I FIG. .5.

INi E'NTOR m a. BoHA/v/vo/v i mm A TI'ORNE Y Patented Jan. 19, 1937 UNITED srArEs METHOD OF AND APPARATUS FOR MANUFACTURING ARTICLES William B. Bohannon, "Westfield, N. 1., assignor to 'Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application April 5, 1934, Serial No. 319,136

7 @laims. -(Cl. 91-55) This invention relates to a method of and apparatus for manufacturing articles and more particularly to a method of manufacturing electrical condensers and to apparatus for practising the method characterized by adaptability to straight-line automatic operation and including an improved method and apparatus for heating and drying articles such as electrical conclensers having metallic internal members.

An object of the invention is to provide a method and an apparatus for drying articles such as electrical condensers and others having metallic internal members by means of heat generated by electrical induction within the metallic members. I

With the above and other objects in view one embodiment of the invention may be a method and an apparatus for manufacturing electrical condensers of the stack. type in which the assembled condensers are advanced on a conveyor and are subjected successively to automatically acting means to heat, evacuate, and impregnate them with a moisture proof sealing material, an ancillary part of the invention being the method of and means for heating the condensers to drive out moisture therefrom which include the step of and means for subjectingthe condensers to the magnetic field within a conductive helix carrying a current of electricity of high frequency and which may include the step of and means for subjecting the condensers to evacuation and to a non-oxidizing gas such as carbon, dloxid or nitrogen before, during or after the heating. The heating is occasioned by electro-magnetic effects such as eddy currents or hysteresis losses generated by the rapidly alternating magnetic field within the metal foils and other metallic parts of the condensers. Satisfactory heating throughout and thorough 40 drying is thus attained in a period of minutes or even seconds as compared with the hours or even days required if an oven be used.

Other objects and features of the invention will appear from the following detailed descrip- 45 tion of one embodiment of the invention in a method and an apparatus for manufacturing electrical condensers taken in connection withthe accompanying drawings in which the same reference numerals are applied to identical elements in the several figures and in which Fig. 1 is a partly diagrammatic broken view of an apparatusconstructed in accordance with the invention for automatically heating, drying, evacuating, and gas charging condensers, and

then impregnating them with sealing compound all according to the method of the invention;

Fig. 2 is a detached enlarged view in left hand end elevation of the combined fluid and electrical current control assembly thereof;

Fig. 3 is a view on the line 33 of Fig. 2;

' Fig. i is a view similar to Fig. l of a modified form of impregnating means, and

Fig. 5 is an enlarged broken view in central vertical longitudinal section of the upper left hand portion of Fig. a.

In the apparatus disclosed in Figs. 1 and 2, a belt conveyor generally indicated by the numetal 2% is associated with a heating unit generally indicated at to and a dipping or impregnating unit generally indicated at idii.

The conveyor 253 may be of any approved construction and is not disclosed here in detail as the mode of its construction and operation is not generally relevant to the invention. It may, however, be thought of as a belt 2?! of leather, canvas and rubber, or the like carrying hooks 22 or other suitable devices preferably of nonmetallic material for detachably supporting electrical condensers ill shown as of the stack or pack type; by" the protruding terminals ll of the condensers. The belt 2i may be thought of as running over pulleys 23 and 24, one or both of which may be driven by motor means not shown.

The lower half of the horizontally disposed belt runs in the direction of the arrow over an appropriate part of its path with its upper face in contact with and supported at certain times by a backing member 25 here shown as a simple paralleloplpedal block preferably of non-metah llc material supported by any suitable means not shown. A vertically oriented rod 26 having a function to be described later, is mounted as shown in the left end of the block 25 and passes down past the rear edge of the belt.

The heating unit 40 comprises a base block 4| having a cylindrical chamber 42 hereinafter termed the cylinder 42, therein. A piston 43- in the cylinder carries a vertically oriented piston rod 44, the upper end of which is pivoted on a shaft 45 mounted in an oven block 45 arranged to be moved up and down by the piston and piston rod and guided by guide rods 47 integral with the oven block and sliding in corresponding bores in the base block. An air bore 48 leads from the cylinder 42 to a compressed air supply pipe 49 which enters a con trol box 50 and is connected via a valve 5| to a pipe 52 leading to a source of compressed air not shown. The valve 6! is mounted on a shaft "rotated by'a lever arm 53 thereon. A second valve 55 on the same shaft 54 behind (Fig. 2) the valve 5I communicates at one side with the bore 48 and at the other side with an open exhaust vent or pipe 56. A third valve 51 also on the shaft 5I communicates at one side with the compressed air pipe 52 and at the other side with a vertical riser 38 by way of a pipe 6|, and a fourth valve 58 also on the shaft 5i connects a vacuum line 58 to the riser 38 by way 01 a pipe 68.

On the top of the oven block 46 is located a series of inverted bell jars 62, and in each jar is mounted an insulated conductive helix 63 with its axis vertical and concentric to the bell Jar. Each jar is entered by a pipe 84 leading to a horizontal bore 65 in a valve block 68 left hand face (Fig. 1) of the oven block. Bore 85 passes through a cylindrical valve recess vertically disposed in the block 66 andcommunlcates by way of a telescopic connection 68 with the riser 38. A spring pressed valve pis ton 89 in the valve recess closes the bore 65 normally, but is displaceable downwardly by the rod 28, to open the bore 65.

Leads II from the helices 83 run to and enter the housing 61. Power supply leads 12 from any suitable electrical power source not shown also enter the housing 61. Power control leads I3 and I4 run from the housing to the control box 58, lead I3 being connected to an insulated terminal I5 on the box and lead I4 being connected to the shaft 5|. Terminal I5 is so positioned as to be in contact with lever arm 53 in one extreme position thereof to close a air cuit through leads l3 and I4.

The devices housed in the housing 61 are all well known and their nature and construction form no part of andare irrelevant to the present invention. from one of the leads I2 enters lead I3 or I4 and returns to the housing via lever arm 53 and contact I5 and lead I4 or I3. Here it is used to produce an alternating current of high. frequency whch is fed through the leads II to the helices 63. In one instance the current thus fed to one helix was of. a frequency of the order 01' 500 kilocycles and had an effective amperage t 30. This current will flow only when lever arm 53 is in contact with terminal I5.

Lever arm 53 is housed within the box 56 and carries at each end one of a pair of slides I8 and 11 mounted pivotally on the lever arm and free to slide respectively in arcuate slots 18 and 19 in the wall or the box 58.

A large gear wheel 88 is mounted on a stub shaft journalled in the base block H and is driven through appropriate gears by a motor 8|. Two pins 82 and 83 aremounted in the side or the wheel 88 in position to strike against the slides 18 and I1 respectively if either of these be at the left hand end (Fig. 2) of its arcuate guide slot, and to carry the slide from left to right in the slot, the slot being so curved as to carry the slide out of contact with the pin at the right hand end 01' the slot. Thus pin 82 acts to turn the shaft i clockwise (Fig. 2) and pin 83 acts reversely.

The dipping or impregnating unit I80 comprises a base block I4I which may or may not be continuous with the base block 4| oi the heating unit. A large gear wheel I80 is rotatably mounted in an appropriate recess '0! the block I on a shalt journalled therein and Suffice it to say that current is driven through appropriate gearing and shafting by the motor BI or by an independent motor as desired. A connecting rod I44 is pivoted at its lower end to the wheel I80 and at its upper end to a vertically reciprocable tank block I46 having guide rods sliding in corresponding bores in the base block I4I. An impregnating tank I62 adapted to hold a bath of normally liquid or of molten impregnating and sealing compound is carriedon the block I46 and is provided with means such as an electric heating coil I84 to heat the compound if de sired. The tank is open on top and may be slightly narrower from front to back than the belt 2i and be provided around its top edge with a sealing member I85 of rubber or the like to be pressed against the belt when" the rigidly mounted on a housing 61 attached to the tank is at the upper limit of its travel.

A drip tank I86 independent of the impregnating tank I62 may be provided beyond the latter to the right if desired to catch excess liquid dripping from condensers after impregnation.

The gear wheels 80 and I88 are driven continuously and in synchronism to reciprocate the blocks 46 and I46 in a timed relationship as hereinafter described. The belt 2i is driven intermittently in timed relationship to the motion of the block 46 as hereinafter described. Mechanism to cause and control the synchroniaed motions of the belt 2| and the block 46 is not shown or disclosed as the nature and structure of such devices are well known and are not pertinent to the present invention, and a detailed showing and description thereof would be confusing and tend to befog the clarity of the explanation of the invention proper. For that matter, the belt 2| could be pulled along by hand.

The operation of the apparatus thus far disclosed is as follows:

Assembled electrical condensers which are to be baked and impregnated may be placed by hand upon the hooks 22 at the left of Fig. 1 near the pulley 23 by an attendant. The belt is then moved along, manually or automatically, while the blocks 48 and I46 are in their lowest positions until a series of untreated condensers equal in number to the number of bell Jars 62 is positioned over the latter in l-to-l relation thereto.

In due course the pin 83 carries the slide ll from left to right (Fig. 2) in the slot 19 turning the lever 53 counterclockwise and carrying the slide I8 to the left end of the slot I8 thus rotating the valve shaft 5| counterclockwise. This action opens the valves 54 and 58, closes the valves 55 and 51 and closes the electrical circuit through leads I3 and I4 thus supplying high frequency current to the coils 63. Compressed air is thus admitted to the passage 48 and. the cylinder 42, and the riser 38 'and telescopic connection 68 are evacuated. The piston 43 rises driving the block 46 up until the open mouths of the bell jars 62 are sealed by contact with the resilient belt backed by the block 25 and each of the condensers now in question stands in the magnetic field within one of the now energized coils 63. As the bell Jars come into contact with the belt, the rod 28 opens the bore 65 by pushing down the valve piston 89, and the bell jars are evacuated by way of the connection 88 and the pipe 38. The effect of the intense and rapidly alternating magnetic fields is to generate electro-magnetic effects such as eddy currents or hysteresis losses within the metal parts of the condensers within the coils 63. These currents convert their energy into heat generated within the condensers, which rapidly and efiiciently drives out any moisture occluded therein aided by the evacuation of the bell jars.

After an appropriately predetermined interval dependent on the rotational speed of the wheel 80, the pin 82 moves the lever arm 53 clockwise (Fig. 2) thus opening the circuit T3--'|4 at the terminal 15, opening the valves 55 and 51, and closing the valves 54 and 58. The result is that heating of the condensers stops as current is cut off from the coils 83, and the vacuum line is closed at 59; immediately after this compressed air enters the riser 38 from the valve 51 by way of pipe BI and releases the suction of the bell jars on the belt. Immediately after this, the air pressure in the cylinder 42 through the exhaust valve 55 and the pipe 58, and the block 46 drops by gravity to its lowest position. The belt 28 then moves automatically or is pulled along to bring a fresh batch of condensers into position for baking and evacuation. Valves 58, 54, 55 and 51 are so constructed that the above described operations follow in the sequence stated.

In case it is desirable for any reason to bake the condensers in an inert gas or in a reducing atmosphere or the like, pipe 59 may be'connected to a source of carbon dioxide, nitrogen, hydrogen,

.or the like appropriate gas under pressure instead of to an exhaust device. In. this case valve 58 and valve 69 may beset to open alittle before the bell jars reach their uppermost position.

, When the belt 2| is stepped along to carry the batch of baked condensers away from the heating unit 40, it comes to rest with the condensers in position above the tank I62 and remainsthere while the wheel 18!! makes one or more revolutions. At each revolution the wheel carries the tank up and immerses the hot condensers in the.

contents of the tank I62.

At the next progression of the belt, the dripping and cooling condensers stop over the drip tank I86.

If a cooling dip is found to be desirable, the apparatus of the impregnating unit I may be duplicated to the right thereof and this additional tank supplied with a bath of cooling oil, or a supply of cold compressed air.

If it be thought best to impregnate the baked and hot condensers in a vacuum or in a special atmosphere or under pressure, the apparatus disclosed in Figs. 4 and 5 may be substituted for the unit I00 of Fig. 1.

In this arrangement the base block 2 is like that of unit 40 in Fig. 1, with a compressed air cylinder 242, piston 243 and connecting rod 244 adapted to raise and lower a tank block 246 provided with a series of individual bath recesses 262 corresponding in number to the number of condensers to be simultaneously treated. Each recess has a vertically reciprocablepiston 281 forming its floor. Each recess is further provided if desired with heating means 284.

A backing block 225 which may or may not be unitary with the block 25 holds the belt against the thrust of the block 246.

A passageway 288 leads from the bottom of the recess belowvthe piston 281 to a bore 289 in a valve block 266 rigidly attached to the. tank block, and another branch 290 of the same passage leads from the bore 288 to a bore 2" is released communicatingwith the interior of the recess 282 near its upper end. A second bore 292 in the valve block communicates with a bore 293 which also enters the recess 262 near its upper end.

A spring pressed slide valve 269 in the block 268 serves tol open or close both bores 289 and carried by the block 225. A second spring pressed slide valve 294 serves to open and close the bores 29! and 293 and is actuated by the piston 281.

A telescopic or flexible connection 268 leads from the bore 292 to a riser 238 which in turn is connected to a valve 258 coupled to a vacuum line. A similar connection 388 leads from the bore 289 to a riser 338 and a valve 254 coupled to a compressed air line. From the valve 254 a further passageway 248 leads to the cylinder 242. Also an exhaust or vent 256 is connected to the passageway 248 by way of a valve 255.

The three valves 254, 255 and 258 are mounted on and actuated by a common shaft 25! and operated by a mechanism like that in unit 40 of Fig. 1, including a gear wheel 280 with pins 282 and 283 to shift a lever arm 253. The wheel 280 may be driven through appropriate gears and shafts by the motor 8| or by an independent motor. In any case wheels 280 and 80 must be properly synchronized.

I In operation, the belt 2| having come to rest with a batch of baked condensers inproper position above the block 248, the pm 283 throws the valve lever 253 over opening the compressed air supply valve 254 and the vacuum line valve 258, and closing the exhaust valve 255. At this time the valve 269 has closed both bores 289 and 292. Thus air is admitted underpressure' below the piston 243 which rises carrying the block 264 up into contact with the belt 2| and positioning a condenser in the recess 262 but not yet immersed as the piston 28! is down. As the block 246 comes to a halt the rod 226 pushes the valve block 269" down opening the bores 289 and 292. The recess above the surface of the liquid therein is evacuated through the bores 293 and 292 and through the riser 268 and valve 258.

At the same time compressed air is admitted via the passage 288 under the piston, 28'! which rises until it is stopped by a stop shoulder 295 in the recess 262. During the latter part of this motion the piston 281 .lifts the slide'valve 294 closing the bore 288 and opening the bore 2!, thus cutting off the vacuum line from the recess and admitting pressure air above the liquid.

In due course pin 282 rotates the lever arm 253 to close valves 258 and 254 and to open valve 255. The air in the cylinder 242 is then exhausted through the vent 256 and the piston 243 descends bringing with it the block 248. At the same time the air under the piston 28'! exhausts through .passage 288, bore 289, riser 368 and vent 256, the valve 269 having closed the bore 292 as the block 246 descended. The piston 28! descends swiftly owing to the initial pressure of air on the surface of the liquid and to its relatively small size, so that it has reached its lowest position within the block 246 before the valve 269 has closed the bore 289.

The belt 2| may then be stepped along to bring the freshly impregnated condensers over the drip tank I88 and a new batch of condensers over the block 246 for impregnation.

292, and is actuated by a. rod 228 conveniently In some methods and apparatus heretofore in use, articles of the general character described, 1. e. characterized by having metal interior parts have been dried or otherwise subjected to a baking process by being heated in an oven. In the case of one particular type of stack or pack condensers a treatment of upward of five or six hours at temperatures of the order of 250 F. was necessary to ensure driving the heat into the article enough to dry it completely throughout.

In the practise of the present invention it has been found that complete drying of the same type of condenser is effected by induction in the simple induction furnace described, in a period of time measured by seconds or at the most of the order of two or three minutes.

This shortening of the time required for the drying or baking enables the manufacture of such articles by at least partly automatic methods in continuous fashion since the articles may thus be treated in rapidly successive small batches on a conveyor instead of having to be accumulated in large numbers for economical simultaneous treatment in a large oven.

A characteristic feature of the invention which permits of this saving of time and consequently of the improved mode of manufacture is the production of heat within the article to dry it, or for any other purpose,by means of electro-magnetic effects such as eddy currents or hysteresis losses generated in metal parts within the article by induction in a varying magnetic field. The article is simply placed in the field, and no complications of connecting each article to and disconnecting it from a current source are necessary.

The embodiments of the invention in methods and in apparatus disclosed herein are merely illustrative and may be departed from and modified in many ways without departing from the scope and spirit of the invention as pointed out in and limited only by the appended claims.

What is claimed is:

1. A method of impregnating articles having internal metal parts surrounded by heat insulating material which comprises the steps of immersing such an article in a magnetic field of varying intensity to generate heat within the article from elec-tro-magnetic effects induced within a metal part while simultaneously subjecting the article to a dry inert gas to drive moisture out of the article thereby, and treating the dried article with a liquid material to innpregnate the same therewith.

2. In an apparatus for treating articles having internal metal parts, an open mouthed housing, means to close the housing, a conductive helix concentric with the housing, means to supply an alternating electric. current to the helix, and

means to create a vacuum within the housing, in combination with means to treat an article with liquid material.

3. In an apparatus for treating articles having internal metal parts, an open mouthed housing, means to close the housing, a conductive helix concentric with the housing, means to supply an alternating electric current to the helix, and means controlled by the first mentioned means to alter the atmospheric state within the hous- H18.

4. In an apparatus for treating articles having internal metal parts, an open mouthed housing, means to close the housing, a conductive helix concentric with the housing, means to supply an alternating electric current to the helix, and means to create a vacuum within the housing.

5. An apparatus for impregnating articles having internal metal parts, which comprises a conveyor to carry articles, a first station and a second station associated therewith, drying means at the first station comprising a reciprocable support, an open mouthed housing thereon adapted to be closed by the conveyor in one position of the support, a conductive helix concentric with the housing, and means to supply alternating electric current to the helix, and im pregnating means at the second station comprising a reciprocable support and a tank thereon for containing liquid material.

6. An apparatus for impregnating articles having internal metal parts, which comprises a conveyor to carry articles, a first station and a second station associated therewith, drying means at the first station comprising a reciprocable support, an open mouthed housing thereon adapted to be closed by the conveyor in one posltion of the support, a conductive helix concentric with the housing, means to supply alternating electric current to the helix, and means to draw gases and vapors from the housing, and impregnating means at the second station comprising a reciprocable support and a tank thereon for containing liquid material.

7. An apparatus for impregnating articles having internal metal parts, which comprises a conveyor to carry articles, a first station and a second station associated therewith, drying means at the first station comprising a reciprocable support, an open mouthed housing thereon adapted to be closed by the conveyor in one position of the support, a conductive helix concentric with the housing, means to supply alternating electric current to the helix, and means to draw gases and vapors from the housing and to supply other gases to the housing, and impregnating means at the second station comprising a reciprocable support and a tank thereon for containing liquid material.

WIILIAM B. BOHANNON. 

